1. Field of the Invention
The present invention relates to control devices for controlling the amount of power delivered from an alternating-current (AC) power source to an electrical load, and more particularly, to a load control device that may be converted from being configured as an electronic switch to being configured as a dimmer switch after installation.
2. Description of the Related Art
Typical load control devices are adapted to be coupled in series between an alternating-current (AC) power source and an electrical load, such as a lighting load or a motor load, for control of the power delivered from the AC power source to the electrical load. Wall-mounted load control devices are adapted to be mounted to standard electrical wallboxes. A standard mechanical switch may be switched between a closed state (in which power is delivered to the load and the load is on) and a closed state (in which power is not delivered to the load and the load is off). An electronic switch (i.e., a digital switch) comprises a controllably conductive device (such as a relay or a bidirectional semiconductor switch, e.g., a triac), which is coupled in series between the power source and the load and is controlled to be conductive and non-conductive to toggle the electrical load on and off, respectively. A typical electronic switch comprises a microprocessor (or similar controller) for controlling the controllably conductive device and a power supply for powering the microprocessor. In addition, the electronic switch may comprise, for example, a memory, a communication circuit, and a visual indicator, e.g., a light-emitting diode (LED), which are all powered by the power supply.
A dimmer switch is operable to control the amount of power delivered from the AC power source to the electrical load, e.g., to control the intensity of a lighting load. A typical dimmer switch comprises a bidirectional semiconductor switch (such as a triac) coupled in series between the power source and the load. The semiconductor switch is controlled to be conductive and non-conductive for portions of a half-cycle of the AC power source to thus control the amount of power delivered to the load (e.g., using a phase-control dimming technique). A “smart” dimmer switch (i.e., a digital dimmer switch) comprises a microprocessor (or similar controller) for controlling the semiconductor switch and a power supply for powering the microprocessor. The smart dimmer switch may also comprise a memory, a communication circuit, and a plurality of light-emitting diodes (LEDs) for providing feedback of the intensity of the controlled lighting load.
After installation of an electronic switch, a user of the switch may desire to upgrade the electronic switch to a dimmer switch to provide for control of the specific amount of power delivered to the controlled electrical load. Thus, there exists a need for an electronic switch that may easily be converted into a dimmer switch after installation.